The present invention relates to a cleaning roller for the head cylinder of a magnetic tape unit and, particularly, for the type of head installed on a rotating cylinder or drum.
In general, a head cylinder is apt to incur malfunctions due to grazing caused by air-borne dust or magnetic powders evolving when said head cylinder scans onto the magnetic tape, always resulting in very intensive requests for cleaning said head cylinder, particularly in the case of video heads.
Heretofore, as shown in FIG. 7, such cleaning has been performed by means of a roller 2 to contact with the surface of a head cylinder 1, wherein said roller 2 is installed rotatably at the end of an arm 5 fixed turnably to a chassis 4, and said roller 2, as shown in FIG. 4, comprises a pad 7 wound around a cylindrical core 6, having an insert hole, with even diameter throughout, to receive a support shaft 8 secured to said arm 5.
Contacting of said roller 2 with the surface of said head cylinder 1 is performed by electrically or mechanically vibrating said arm 5, being synchronized with head cylinder for a certain while during the inertia term of a video head 3, except when video-recording or video-regenerating, at the start of loading, or, since the termination of video head (Jpn. Pat. Publn. No. Sho 60-20251).
The video head 3 is installed to said rotating head cylinder, projecting by 30-60 .mu.m from the surface of said cylinder 1. Therefore, as shown in FIG. 4, the surface 7a of a cleaning roller 2 shall, always, be contacted evenly with said cylinder 1, otherwise resulting in poor cleaning effects due to the elimination of said contact whatsoever.
The known roller 2, however, as shown in FIG. 4, is very sensitive to vibrations of the axis of a shaft 8, being able to effect even and close contact of said surface 7a with said head cylinder 1 only when the axis 8a of said shaft 8 is parallel to said head cylinder 1. However, in case of axis vibration, as shown in FIG. 5 or FIG. 6, in the prior art, poor cleaning effects have emerged due to clearance between said surface 7a and said cylinder 1.
Thus, it has been extremely difficult to make perfect alignment of said shaft 8. Besides, any irregularity or unevenness during the manufacturing process of unit components, such as said arm 5, said shaft 8 and said cylinder 6, has also resulted in said poorness in cleaning.